Abstract: The invention concerns a roller (R), used in continuous product heating furnaces for handling and conveying steel products and in particular slabs. The associated apparatus includes a cooled central shaft (1), cooled by a liquid. On the shaft are mounted a plurality of discs (2), for supporting the products (3) to be transported, arranged perpendicularly to the longitudinal geometrical axis of the roller (R), spaced apart along the axis of the roller (R) and separated by an insulating sleeve (4). The insulating sleeve (4) is maintained at each longitudinal end by at least one cold component (5) secured to the shaft (1) and cooled by the shaft, with axial play (Ja) between the sleeve (4) and the shaft (1) such that possible sagging of the shaft (1) may occur in use without causing substantial mechanical stress on the insulating sleeve (4) and the heat transferred from the sleeve (4) to the shaft (1), and from the discs (2) to the sleeve (4) is limited.

Abstract: The invention relates to a method for controlling the homogeneity of the temperature of metallurgical products (B) in a reheating furnace (5) fitted with lateral burners. According to said method, the lateral burners are operated by on/off control, and the operating time and the down time of each burner is regulated in order to obtain the desired temperature. Inshot burners (1-4) are used as the lateral burners. Said burners are operated either at a speed which is close to the maximum speed or at the maximum speed, and the ignition order of the burners (1-4) is selected in such a way as to stimulate the stirring and circulation of the fumes in order to reduce the hot spot of the flame and to improve the homogeneity of the temperature of the walls of the furnace and the products.

Abstract: A process is disclosed for the continuous thermochemical treatment of metal strip. It is useful with steel strip, of the oxidation-reduction type, in which the strip moves through a furnace in a protective atmosphere. The strip passes through at least one partial or total isolation device positioned within one or more sections of the furnace. The strip is heated in this isolation device in atmospheres having a dew point tailored to each strip according to the specific composition of the steel so that the atmosphere is oxidizing in the case of certain addition elements, but remains reducing in the case of iron.

Abstract: An analysis and control device for glass furnaces is of the fuzzy-controller type and uses a control algorithm which receives information relating to the operation of the furnace coming from sensors and from detection means provided on this furnace, as well as set point values input manually by operators. This control algorithm delivers control signals to the various actuators and control means of the furnace. A predictive system, of the neural- and/or fuzzy-type is included which depends on the state of the furnace and on the information about the change in production over time. It defines the various set point values to be assigned to all the furnace actuators, so as to ensure optimum operation for each production phase. The set point values constitute input values for the fuzzy-logic algorithm which controls the furnace.

Abstract: Process for the continuous hot-dip galvanizing of a steel strip (1) containing oxidizable addition elements in a proportion allowing the mechanical properties of the steel to be improved, in which process the strip passes through a galvanizing furnace (3) in a reducing atmosphere, this furnace consisting of heat treatment sections, for heating, soaking and cooling, and is then dipped into a galvanizing bath (2). The strip is subjected, upstream of the inlet section of the furnace, to an oxidation treatment under conditions as regards temperature, duration and oxygen content of a gas in which the strip is immersed, such that the oxidizable addition elements are essentially oxidized within the strip, before they can migrate to the surface in order to form thereat an oxide layer.

Abstract: Flat glass annealing lehr equipped with controlled heating and cooling means, includes pre-annealing, annealing, and post-annealing zones with heat exchange by radiation, the said zones being equipped respectively with groups of cooling-air heat exchangers situated above and/or beneath the glass ribbon. A single cooling-air intake manifold is included for groups of exchangers in the pre-annealing and annealing zones, which manifold is situated where the zones meet. A single cooling-air intake manifold for second groups of exchanges in the annealing and post-annealing zones, which manifold is situated where said zones meet.

Abstract: A method is disclosed for preheating a metal strip in at least one direct fired preheating section of a furnace for limiting the oxidation of the metal strip. The method includes installing burners in the preheating section along its length for establishing a plurality of preheating sub-zones of unit length corresponding to one burner. The air and fuel settings for each burner are adjusted in accordance with a desired heat demand. Subsequent steps include operating a variable number of downstream burners at full power to establish a preheating zone of variable length to produce the desired heat demand, and extinguishing a second variable number of upstream burners to establish a corresponding variable recovery zone.

Abstract: Process for preheating metal, especially steel strip in direct-fired preheating sections for the purpose of limiting the oxidation of the heated metal strip, whatever the production configurations, which consists in using a preheating zone that can be divided, along its length, into a plurality of zones of unit length corresponding to one burner, it being possible for each of the said burners to be operated individually under fixed conditions so as to accurately adjust its air/gas setting, and therefore the resulting atmosphere in the furnace, wherein a certain number of burners starting from the downstream end of the preheating zone are ignited, the length of the furnace zone affected by the ignition of the said burners and the length of the recovery zone, i.e. the zone in which the burners are extinguished, being variable depending on the heat demand and in that each burner operates at full power and with a constant air/gas setting.

Abstract: A method is disclosed for reducing the formation of wrinkles on metal strip subject to cooling in continuous heat treatment lines in which the strip passes through cooling zones through which cooling gas flows. The method includes the step of gradually modifying the cooling intensity at each change in the slope of the cooling cycle.

Abstract: A flat-flame burner for reheat, holding, and heat-treatment furnaces for treating iron and steel products. It has at least one fuel-injection pipe lying along the axis of the body of the burner, a combustion tunnel and a combustion-air feed, the air being distributed in and by the body. The fuel is introduced via the injection pipe or pipes through at least one axial orifice lying in a plane close to the external plane of the combustion tunnel, into the combustion products. This produces a first dilution of the fuel in these combustion products, the fuel/combustion products mixture thus obtained being diluted further in the combustion air.

Abstract: An indirect radiant heating device burns gaseous or liquid fossil fuels for the heat treatment of running products, such as bars, tubes, and strips kept in a protective atmosphere. The device includes a radiant cassette of parallelepipedal shape, with a continuous radiating surface whose cross section, in a plane perpendicular to the axis of the cassette, is delimited by a continuous line which falls inside a rectangle whose height/width ratio is greater than 1.5.

Abstract: Method of reducing the wrinkles formed in heating zones, by radiant tubes, of continuous heat treatment lines for metal strip, such as annealing or galvanizing lines, the said strip passing over transporting and/or return rollers in the said furnaces, the said method, which consists in modifying the thermal state of the rollers, being characterized in that the said modification is made directly by varying the heating by the said radiant tubes located near the rollers, thereby directly controlling the heat flux emitted by the radiant tubes towards the rollers.

Abstract: A fluid-fuel burner of the type producing a flame with axial development, which includes a combustion tile, having a broad shape, provided with an oxidizer and fuel injection orifices. These are approximately parallel to the major axis of symmetry of the tile, the internal shape of the latter as well as the orientation of the fuel and oxidizer injection orifices being chosen so as to create a difference in the distribution of the combustion products and of the recycled flue gases. A spread out flame is produced which ensures homogeneous distribution of the heat flux.

Abstract: Method of making safe a heat treatment enclosure operating under a gas atmosphere, the said enclosure comprising a cooling chamber for rapidly cooling a metal strip running from an upstream chamber to a downstream chamber by means of a plurality of guide rollers, wherein said rapid cooling chamber is filled with a controlled atmosphere with a high hydrogen content and said strip is confined within said rapid cooling chamber by means of at least one pressure-balancing duct and of a plurality of gas locks placed between the various chambers, the pressures of the gas atmospheres between the chambers being balanced by means of ducts controlling the flow rates of the gas flowing through the said gas locks.

Abstract: Method for eliminating vibration of strip travelling continuously through zones of a heat treatment or coating line in which gas is blown onto a strip travelling continuously, particularly through devices which effect cooling by blowing gas in jets with which the lines for the continuous heat treatment or coating of metal strip are equipped, characterized in that this method consists in adjusting the pressure and/or the flow rate of the cooling gas to a value lower than the nominal value in a zone located at one edge of the strip, on one side thereof, and to a value lower than the nominal value on the opposite edge, located on the other side of the strip.

Abstract: A heating furnace reheats batches of iron steel products, which differ in their thermal state, introduced in succession into the furnace. The furnace has heating zones followed by at least two equalization zones, the products passing through at least one of these zones, at a speed different from that of the other zones. This speed can be adjusted depending on the thermal objective for the products to be reheated, and at least one of these zones is used as a heating zone.

Abstract: Rapid-cooling oven, forming part of a plant comprising various treatment stations, especially stations for the heat treatment of products in strip form, through which a metal strip runs continuously, the rapid cooling being obtained by spraying onto the strip a jet of an atmosphere gas consisting of a nitrogen/hydrogen mixture having a hydrogen content which is greater than 15%, and preferably close to 50%, the atmosphere gas being recirculated using a circuit of recirculation ducts comprising compensators made in the form of a series of corrugations allowing all the ducts to expand, at least one fan and at least one gas/water exchanger, wherein a safety device is provided to prevent this ingress of air into the circuit for recirculating the cooling gas or any leak of the latter into the environment, in the event of a break in a corrugation of a compensator or in the case of a leak form the latter, said safety device being made in the form of a flexible membrane impermeable to the cooling gas, the said membra

Abstract: In an apparatus that rapidly cools heat treated metal strips with a recirculating nitrogen-hydrogen cooling gas mixture having a hydrogen content which ranges between 15%-50%, and a recirculation circuit for the gas mixture having a fan for creating a flow though recirculation ducts connected, through expandable compensator corrugations, upstream to at least one gas/water exchanger, a safety system operates with the exchanger. The safety system includes a housing having a main flow area upstream of the exchanger and into which recirculating cooling gas flows. A first register is interposed across the main flow area for selectively switching between open and closed states thereby passing or blocking flow through a major portion of the main flow area. At least one bypass flow area is defined within the housing and located adjacent the main flow area.

Abstract: An assembly for treating metal products is presented. The assembly includes a preheat furnace aligned with a reheat furnace. Cold products are initially heated in the preheat furnace and hot products bypass the preheat furnace. A material handling device is provided for a) transferring preheated products from an outlet of the preheat furnace to an inlet of the reheat furnace, and for b) transferring hot products from a point between the furnaces to the inlet of the reheat furnace. The material handling device includes a support extending between the outlet of the preheat furnace and the inlet of the reheat furnace for receiving preheated and hot products; and a displacement device located below the support means for lifting and translating preheated and hot products from the support means to the inlet of the reheating means.

Abstract: Apparatus which eliminates the risk of forming wrinkles on a strip conveyed through a cooling furnace of a continuous heat-treatment plant, especially an annealing or galvanizing furnace, through which the strip is conveyed by rolls, the latter being heated by contact with the strip over its width, the risk of forming wrinkles occuring during a change of strip width when the following strip is wider, the latter consequently passing over rolls that have preserved the imprint of the thermal expansion due to the previous strip, wherein the heating elements are positioned close to and beneath the rolls, over the entire width of the furnace, and, on the opposite side of the rolls from the said heating elements, panels are positioned which are aligned so as, together with the wall of the furnace, to form a warm chamber, the continuously moving strip serving as a heat shield so that only that part of the roll which is not covered by the strip is heated by the said heating elements.